Longitudinal Changes in Bone Mineral Density and Trabecular Bone Score in Adolescents With Graves' Disease.

OBJECTIVE

Longitudinal data on bone health in adolescents with Graves' disease (GD) are limited. Thus, we aimed to evaluate lumbar spine bone mineral density (LSBMD) and trabecular bone score (TBS) changes in this population.

METHODS

Baseline and follow-up LSBMD Z-score (LSBMDZ) and TBS Z-score (TBSZ) were measured. TBS was analysed using iNsight software.

RESULTS

Forty-one adolescents with GD (age 13.7 ± 2.8 years, 73% female) were enroled. At baseline, 18% of adolescents with recently diagnosed GD (RGD, ≤ 6 months) had low LSBMD (median LSBMDZ: -0.7 [-1.5 to -0.4]), and 58% had low TBS (mean TBSZ: -1.5 ± 1.3). The median follow-up duration was 2.2 (1.2-2.9) years. In the entire cohort, at follow-up, LSBMDZ normalized, whereas TBSZ remained below zero (p = 0.007). Adolescents with RGD and those with longer disease duration had comparable LSBMDZ and TBSZ at follow-up. When stratified by baseline disease duration tertiles, improvements in LSBMDZ (p = 0.013) and TBSZ (p = 0.035) progressively declined with increasing disease duration. LSBMDZ was significantly increased from baseline during 28 months of treatment (p = 0.01), while TBSZ improvement was observed during the initial 9 months (p = 0.046). Stepwise regression identified time-weighted free thyroxine (FT4) as a negative predictor of ∆TBSZ (p = 0.042).

CONCLUSIONS

Low TBS was prevalent among adolescents recently diagnosed with GD. Despite observed improvements, TBSZ remained below zero at follow-up, indicating incomplete recovery. As FT4 negatively impacts TBS improvement, maintaining optimal FT4 concentrations early in the disease is crucial for preserving bone microarchitecture in paediatric GD.